1. Field of the Invention
The present invention relates an information retrieving system, an information retrieving method, and an information retrieving program which can be applied to, for example, retrieval of an electronic document or a word in an electronic document with an arbitrary keyword.
2. Description of the Related Art
A retrieval engine disclosed in the Internet is established as a tool that lists addresses (URLs) of Web pages related to input keywords on the basis of a predetermined order of priority to make it possible to checks any and all things from business articles to objects for pleasure.
However, when a matter (for example, a place or the like) related to a retrieval keyword is desired to be known, a large number of documents in which the matter is not described are listed in a retrieval result in retrieval using only a keyword. Even though the documents include the matter, the documents must be read, and it is difficult to efficiently know the matter.
As a method of solve this problem, a method disclosed in Japanese Patent Laid-open Publication No. 2002-132811 is known. In this method, a question sentence (for example, “What is the capital of Japan?”) is input, after the question sentence is analyzed, a related document is retrieved according to the analysis result. In addition, an answer to the question sentence (for example, “Tokyo”) is obtained and output.
However, in a method described in Japanese Patent Laid-open Publication No. 2002-132811, since an answer is formed on the basis of a document serving as a retrieval result of a keyword to a document database, the retrieval result frequently includes a sentence in which a word serving as an answer is not described, and retrieval efficiency is deteriorated. Furthermore, since the answer is formed by searching the document, long processing time and high processing cost are required when the answer is formed.